I see advice to resort to melatonin, but only if you awaken. I take it at bedtime, and find that it helps me to stay asleep the few nights in a month when I elect to use it. I keep it, and zopiclone, potent by not using them more than about once a week. In fact, since getting over my atrial fibrillation via a second, successful, catheter ablation, I haven't used zopiclone in over 16 months. Don't get me wrong: I do fall asleep quite well, but I just don't stay asleep if I awaken for some reason after, even four whole hours. I can sometimes get back to sleep if I lie there and ruminate for an hour or more, but it's only 50/50 on that account.

I'm not like everyone reading this, and you won't be like me. I tough out the rough nights when I know I'm going to be lucky to get four or five hours, and I'll do this two/three nights running until I take melatonin...3-5 mg only. After a really rough spell, I used to take i/4 tablet of zopiclone because it seemed to do the trick. In fact, because he knew I have sleep apnea, the pharmacist who filled the prescription for one tab as needed suggested I cut each tab in half and to try that. I did, first night, and it worked so well that I felt I really owed it to myself to try the quarter dose. I'd give that quarter tab about a C+ grade, good enough, but not great enough.